Will;
You seem to have found an early use of "lumber crayon". I too looked for information about them without much sucess. I did learn that the word crayon is very vague and means any stick used to write or mark. Often crayons were chalk or chalk mixed with a binder such as wax, grease, or oil. They have been in use for hundreds of years, Leonardo Da Vinci reffered to using crayon. I would be interested to find documentation on when they came into common use.

Raddle, as discussed in the TFWiki, is a red oxide used to mark sheep, snap lines and can be made into a crayon for marking. A synonym of raddle in this form is keel. Marking something was "keeling".

The compound words lumber-crayon and grease-pencil are absent from the Oxford English Dictionary and most others. Here is another research opportunity!

Thanks for sharing.

Jim